Input devices including proximity sensor devices (also commonly called touchpads or touch sensor devices) are widely used in a variety of electronic systems. A proximity sensor device typically includes a sensing region, often demarked by a surface, in which the proximity sensor device determines the presence, location and/or motion of one or more input objects. Proximity sensor devices may be used to provide user interfaces for the electronic system. For example, proximity sensor devices are often used as input devices for larger computing systems (such as opaque touchpads integrated in, or peripheral to, notebook, laptop, and tablet computers). Proximity sensor devices are also often used in smaller computing systems (such as touch screens integrated in cellular phones).
Some input devices also have the ability to detect force applied to a sensing surface in addition to determining positional information. For example, Degner U.S. Patent Application Publication No. 2010/0079404 discloses an input device having a touch-sensitive track pad capable of detecting an X-Y position of an input object proximate the track pad, as well as a movement indicator for detecting movement of the movable track pad. Thus, a user can press down and “click” the pad to simulate a button press. FIG. 3B of Degner illustrates a clickable input pad configured for uniform translation; that is, the entire input surface deflects uniformly regardless of the X-Y location of the applied force. FIGS. 3C and 5 of Degner illustrate a hinged pad which pivots about a hinge, and deflects much like an aileron or door.
Both hinged and uniform clickable pads typically employ a mechanical or electronic switch, such as a rubber or metal domed tact switch, to detect movement of the pad to perform a button click, as well as a spring mechanism to restore the pad to its nominal position following a button click.
Presently known clickable input pads are limited in that the area designated for button clicks tends to limit the area available for proximity sensing. In addition, rigidity of the keyboard deck into which the click pad is mounted is reduced by the presence of the mounting hole. Moreover, a supplemental stiffening layer is typically needed to support the cyclic bending and restoration of glass reinforced epoxy laminate (FR4) or polyethylene terephthalate (PET) circuit boards used in presently known input devices, which increases the cost and complexity of the devices. Devices and methods are therefore needed which overcome these shortcomings.